diff -r 36af3566b67a Lib/test/test_thread.py
--- a/Lib/test/test_thread.py	Thu Nov 03 15:38:58 2016 +0200
+++ b/Lib/test/test_thread.py	Fri Nov 04 11:56:43 2016 -0400
@@ -4,6 +4,7 @@
 from test import support
 thread = support.import_module('_thread')
 import time
+import signal
 import sys
 import weakref
 
@@ -147,6 +148,39 @@
                 time.sleep(0.01)
         self.assertIn("Traceback", stderr.getvalue())
 
+    @unittest.skipUnless(hasattr(signal, "setitimer"), "requires setitimer()")
+    def test_interrupt_main(self):
+
+        # fail after 0.1s: expected SIGINTs were not received while spinning
+        signal.signal(signal.SIGALRM, lambda *args: self.fail("timeout"))
+        signal.setitimer(signal.ITIMER_REAL, 0.1)
+
+        def cleanup():
+            signal.signal(signal.SIGINT, signal.SIG_DFL)
+            signal.setitimer(signal.ITIMER_REAL, 0)
+            signal.signal(signal.SIGALRM, signal.SIG_DFL)
+        self.addCleanup(cleanup)
+
+        # lock: held before interrupt_main(), released when interrupt received
+        lock = thread.allocate_lock()
+
+        # in this context, "main" is the thread running this test,
+        # so instead of catching KeyboardInterrupt, we assert receipt of SIGINT
+        signal.signal(signal.SIGINT, lambda *args: lock.release())
+
+        # code below will only complete (not timeout) if SIGINTs received to
+        # release the lock
+
+        lock.acquire()
+        thread.interrupt_main()
+
+        while not lock.acquire(0):
+            time.sleep(0.01)
+        thread.start_new_thread(thread.interrupt_main, ())
+
+        while lock.locked():
+            time.sleep(0.01)
+
 
 class Barrier:
     def __init__(self, num_threads):